The term deviated lysis (d.l.) describes a particle bound or fluid phase C function, which lyzes unsensitized cells (E) in the presence of EDTA. Its generation via the classical or the alternative pathway has been described. The activity was stable in the fluid phase. It was found in the region of 180,000–220,000 daltons or 9.7S, respectively, and consisted of C5, C6, C7, C8 and C9. Once generated, the activity could be blocked by the respective antibodies, but not by anti-C3 or anti-B.
We now report on a similar activity generated by exposing human serum either to acid pH or low ionic strength. As in C activation by inulin, the factors C5–C9 are involved. Although factor B is converted when normal human serum is brought to pH 6.4, C3 is not. C3, factor B, or properdin, respectively, are not needed. The activation takes place at 0°C within seconds.